| Based on the GIS technology and geo-statistics, the article has studied soil temporal-spatial variation of soil surface(0～20 cm)organic matter, available phosphorus and available potassium from 1981 to 2006 for 25 years in Wafangdian,Liaoning Province.The results from the t-test of paired sample and kriging interpolation indicate that soil nutrient content had sweeping changed by the change of land use, tillage methods and mangagement. From 1981 to 2006,organic matter content increased 1.83 g kg-1 and rose 19.55% and the difference is remarkable. Available Phosphorus content increased 41.53 mg kg-1 and rose 953.84% and the difference is very remarkable. Available potassium content increased 16.76 mg kg-1 and rose 28.77% and the difference is remarkable. The spatial distribution of organic matter, available phosphorus and available potassium have changed in different degrees. Under the influence of the 10～15 g kg-1 grade, the mean of organic matter content rised. But the <5 g kg-1 grade descended a lot. It means that the organic matter has a great consumption, and the organic fertilizer application is insufficient cause the consumption of organic matter is greater than supply and the content is gradually declining. Available phosphorus content has a large increase in recent years mainly with the use of chemical fertilizers increased. Because of the universal application of potassium fertilizer, available potassium has a little increase. However, it has a greater degree of decline in eastern. Available potassium is consumedly influenced by human activities and soil and water loss in these regions. Despite adding the potash fertilizer, potassium content still descend because the adding volume less than consumption. The main reasons that cause the changes in soil nutrient is human factor such as the change of fertilization, tillage and land use.
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